• Journal of the Korean Ceramic Society
• /
• v.52 no.6
• /
• pp.497-501
• /
• 2015

Inkjet printing is a widespread technology, offering advantages such as high-quality decoration, a continuous process, and the accurate direct reproduction of patterns or pictures. In inkjet printing technology, the dispersion stability of ceramic ink is one of the most important factors. In this study, the dispersion stability of blue $CoAl_2O_4$ ink for ceramic inkjet printing is systematically investigated. Blue $CoAl_2O_4$ pigment was synthesized by a solid-state reaction and then milled to less than 300nm in size. In order to investigate the influence of the viscosity on the dispersion stability, two types of $CoAl_2O_4$ ceramic inks (termed here Blue L and Blue H) were prepared using different volume ratios of ethylene glycol and ethanol. The Blue L and Blue H ink solutions contained cetyltrimethylammonium bromide(CTAB) as a dispersive agent. The viscosity, surface tension and jetting stability of the $CoAl_2O_4$ ceramic inks were analyzed using a rheometer, a surface tension meter and a dropwatcher. The dispersion stability of the $CoAl_2O_4$ ceramic ink was investigated by a multiple light-scattering method. Blue H, a ceramic ink with higher viscosity, showed much better dispersion stability than the Blue L ceramic ink.

• Journal of Powder Materials
• /
• v.20 no.3
• /
• pp.210-214
• /
• 2013

This manuscript reports on compared color evolution about phase transformation of ${\alpha}-FeOOH@SiO_2$ and ${\beta}-FeOOH@SiO_2$ pigments. Prepared ${\alpha}$-FeOOH and ${\beta}$-FeOOH were coated with silica for enhancing thermal properties and coloration of both samples. To study phase and color of ${\alpha}$-FeOOH and ${\beta}$-FeOOH, we prepared nano sized iron oxide hydroxide pigments which were coated with $SiO_2$ using tetraethylorthosilicate and cetyltrimethyl-ammonium bromide as a surface modifier. The silica-coated both samples were calcined at high temperatures (300, 700 and $1000^{\circ}C$) and characterized by scanning electron microscopy, CIE $L^*a^*b^*$ color parameter measurements, transmission electron microscopy and UV-vis spectroscopy. The yellow ${\alpha}$-FeOOH and ${\beta}$-FeOOH was transformed to ${\alpha}-Fe_2O_3$ with red, brown at 300, $700^{\circ}C$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.9
• /
• pp.552-558
• /
• 2016

Goethite, ${\alpha}$-FeOOH have various applications such as absorbent, pigment and source for magnetic materials. Goethite particles were synthesized in a two step process, where $Fe(OH)_2$ were synthesized in nitrogen atmosphere using $FeSO_4$ as a raw material in the first process, and after that acicular goethite particles were obtained in an air oxidation process of $Fe(OH)_2$ in highly alkaline aqueous solution. Their phase and microstructure were investigated with XRD and FE-SEM. It was found that the morphology of goethite and the ratio of length-to-width (aspect ratio) of acicular goethite are dependent on the some factors such as R value ($OH^-/Fe^{2+}$), air flow rate and pH conditions. In particular, R value has the strongest influence on the synthesized goethite morphology. It is considered that the optimal value R is 4.5 because X-ray diffraction peaks of goethite have the highest intensity at that value. Morphology of goethite particles was controlled by air flow rates, showing that their size and aspect ratio are getting smaller and decrease, respectively as air flow rate increases. The largest goethite particle obtained is about 1,500 nm in length and 150 nm in diameter.

• Fisheries and Aquatic Sciences
• /
• v.25 no.5
• /
• pp.276-286
• /
• 2022

This study is focused on the effect of phycobiliprotein extraction of Gracilaria on the quality of common carp burgers, and the application of nanoliposomes containing pigment in the improvement of its antimicrobial and antioxidant activity of burgers during refrigerated storage in 18 days. Burgers were incorporated with phycobiliprotein and liposomal phycobiliprotein (2.5% and 5% w/w), and their chemical and microbial changes in terms of pH, peroxide value (PV), thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), total viable counts (TVC), psychrotrophic bacterial counts (PTC), and sensory characteristics were evaluated. Results presented a nanoliposome size of about 515.5 nm with capable encapsulation efficiency (83.98%). Our results showed non-encapsulated phycobiliprotein could delay the deterioration of common carp burgers, as a reduction in PV, TBA, and TVB-N, TVC, and PTC values in burgers treated with free and nano encapsulated phycobiliprotein. Moreover, the potential of phycobiliprotein was improved when it was encapsulated into chitosan coated liposomes. Burgers treated with 5% nanoliposomes displayed the lowest amount of lipid oxidation and microbial deterioration in comparison to others during storage. According to chemical, microbial and sensory evaluation, the shelf life of common carp burgers was increased in samples treated with encapsulated phycobiliprotein at 2.5% and 5%, as compared to the control (p ≤ 0.05).

• Korean Journal of Microbiology
• /
• v.46 no.3
• /
• pp.262-269
• /
• 2010

To investigate a quantitative evaluation of the actinobacteria, we have collected samples from various kinds of bamboo forest soil. Each different layers contained $2.7{\times}10^6-2.7{\times}10^8$ CFU/g of actinobacteria which was the highest in litter layers of Sasa boreali forest soil. We obtained 330 actinobacteria from different layers of bamboo forest soil; litter (100 strains), humus (70 strains), and rhizosphere soil (160 strains). Based on the colony morphology (aerial mycelium, substrate mycelium, and soluble pigment), isolates were divided into thirty-six groups and we selected 50 representative isolates. 16S rRNA gene sequence analysis showed Streptomyces was major actinobacteria (94%) and they were categorized as cluster I (2 strains), II (35 strains), III (6 strains), and IV (7 strains), respectively. The diversity index of 50 Streptomyces collected from the bamboo forest soil was calculated with the Shannon-Wiener method. Bamboo litter showed higher diversity index level of 3.33 than that of humus and rhizosphere soil. Also, antibiotic activities of our isolates were investigated against Botrytis cinerea, Xanthomonas campestris, Xanthomonas axonopodis pv. vesicatoria, and Bacillus cereus and found in 74, 16, 25, and 24 strains, respectively.

• Korean Journal of Remote Sensing
• /
• v.36 no.6_1
• /
• pp.1339-1348
• /
• 2020

Phytoplankton controls marine ecosystems in terms of nutrients, photosynthetic rate, carbon cycle, etc. and the degree of its influence on the marine environment depends on their physical size. Many studies have been attempted to identify marine phytoplankton size classes using the remote sensing techniques. One of successful approach was the three-component model which estimates the chlorophyll concentrations of three phytoplankton size classes (micro-phytoplankton; >20 ㎛, nano-; 2-20 ㎛ and pico-; <2 ㎛) as a function of total chlorophyll. Here, we examined the applicability of Geostationary Ocean Colour Imager (GOCI) to the mapping of the phytoplankton size class distribution in the East Sea. A fit of the three-component model to a biomarker pigment dataset collected in the study area for some years including a large harmful algal bloom period has been carried out to derive size-fractioned chlorophyll concentration (CHL). The tuned three-component model was applied to the hourly GOCI images to identify the fractions of each phytoplankton size class for the entire CHL. Then, we investigated the distribution of phytoplankton community in terms of the size structure in the East Sea during the harmful Cochlodinium polykrikoides blooms in the summer of 2013.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.25 no.1
• /
• pp.20-26
• /
• 2015

Ceramic ink-jet printing technology in art tiles, decorated tablewares and other porcelain products has many advantages of fast and precision printing of various images with high efficiency and low cost. For the application to ink-jet printing, ceramic ink requires a stable dispersibility with nano-sized pigments. In this paper, characteristics of pink-red aqueous ceramic ink for ink-jet printing was demonstrated. $CaCr_{0.1}Sn_{0.8}SiO_5$ pigment was synthesized using solid state reaction and deagglomerated using attrition milling. The aqueous ceramic ink contains 10 wt% of the obtained $CaCr_{0.1}Sn_{0.8}SiO_5$ nanopigment with 0.4 wt% of sodium dodecyl sulfate (SDS) as a dispersion agent. Viscosity of $CaCr_{0.1}Sn_{0.8}SiO_5$ aqueous ceramic ink was adjusted using 0.18 wt% of polyvinyl alcohol (PVA) for a suitable jetting from the nozzle. The prepared pink-red ceramic ink showed a good jetting property with formation of a single sphere-shaped droplet after $180{\mu}s$ without a tail and satellite droplet.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.2
• /
• pp.592-599
• /
• 2019

This study is to stabilize insoluble and unstable active ingredient which is Idebenone (INCI name: hydroxydecyl ubiquinone) in a multi-lamellar vesicle (MLV) and to stabilize it in the skin care cosmetics. Idebenone is good effective raw material in the treatment of Alzheimer's disease in the medical field and a powerful antioxidant in dermatology. It is well known as a substance that inhibits the formation of melanin and cleans the skin pigment. However, it did not dissolve in any solvent and it was difficult to apply in cosmetic applications. Niosome vesicle was able to develop a nano-particle by making a multi-layer of idebenone encapsulated with a nonionic surfactant, hydrogenated lecithin and glycine soja (soybean) sterols and passing it through a high pressure microfluidizer. Idebenone niosome vesicle (INV) has been developed to have the ability to dissolve transparently in water and to promote transdermal penetration. The appearance of the INV was a yellowish liquid having specific odor, and the particle size distribution of INV was about 10~80 nm. The pH was 5~8 (mean=6.8). This capsulation with idebenone was stored in a $45^{\circ}C$ incubator for 3 months and its stability was observed and quantitatively measured by HPLC. As a result, the stability of the sample encapsulated in the niosome vesicle (97.5%) was about 66.3% higher than that of the non-capsule sample of 32.5%. Idebenone 1% INV was used for the efficacy test and clinical trial evaluation as follows. The anti-oxidative activity of INV was 38.2%, which was superior to that of 12.8% tocopherol (control). The melanin-reducing effect of B16 melanoma cells was better than INV (17.4%) and Albutin (control) (9.6%). Pro-collagen synthesis rate was 128.2% for INV and 89.3% for tocopherol (control). The skin moisturizing effect was 15.5% better than the placebo sample. The elasticity effect was 9.7% better than the placebo sample. As an application field, INV containing 1% of idebenone is expected to be able to develop various functional cosmetic formulations such as skin toner, ampoule essence, cream, eye cream and sunblock cream. In addition, it is expected that this encapsulated material will be widely applicable to emulsifying agents for skin use in the pharmaceutical industry as well as the cosmetics industry.